This invention relates generally to the structure of soles of shoes and other footwear, including soles of street shoes, hiking boots, sandals, slippers, and moccasins. More specifically, this invention relates to the structure of athletic shoe soles, including such examples as basketball and running shoes.
Still more particularly, this invention relates to variations in the structure of such soles using a theoretically ideal stability plane as a basic concept.
The applicant has introduced into the art the concept of a theoretically ideal stability plane as a structural basis for shoe sole designs. The theoretically ideal stability plane was defined by the applicant in previous copending applications as the plane of the surface of the bottom of the shoe sole, wherein the shoe sole conforms to the natural shape of the wearer's foot sole, particularly its sides, and has a constant thickness in frontal or transverse plane cross sections. Therefore, by definition, the theoretically ideal stability plane is the surface plane of the bottom of the shoe sole that parallels the surface of the wearer's foot sole in transverse or frontal plane cross sections.
The theoretically ideal stability plane concept as implemented into shoes such as street shoes and athletic shoes is presented in U.S. Pat. No. 4,989,349, issued Feb. 5, 1991 and U.S. Pat. No. 5,317,819, issued Jun. 7, 1994, both of which are incorporated by reference, as well as U.S. Pat. No. 5,544,429 issued Aug. 13, 1996; U.S. Pat. No. 4,989,349 issued from U.S. patent application Ser. No. 07/219,387. U.S. Pat. No. 5,317,819 issued from U.S.patent application Ser. No. 07/239,667.
This new invention is a modification of the inventions disclosed and claimed in the earlier applications and develops the application of the concept of the theoretically ideal stability plane to other shoe structures. Each of the applicant's applications is built directly on its predecessors and therefore all possible combinations of inventions or their component elements with other inventions or elements in prior and subsequent applications have always been specifically intended by the applicant. Generally, however, the applicant's applications are generic at such a fundamental level that it is not possible as a practical matter to describe every embodiment combination that offers substantial improvement over the existing art, as the length of this description of only some combinations will testify.
Accordingly, it is a general object of this invention to elaborate upon the application of the principle of the theoretically ideal stability plane to other shoe structures.
The purpose of this application is to specifically describe some of the most important combinations, especially those that constitute optimal ones.
Existing running shoes are unnecessarily unsafe. They profoundly disrupt natural human biomechanics. The resulting unnatural foot and ankle motion leads to what are abnormally high levels of running injuries.
Proof of the unnatural effect of shoes has come quite unexpectedly from the discovery that, at the extreme end of its normal range of motion, the unshod bare foot is naturally stable, almost unsprainable, while the foot equipped with any shoe, athletic or otherwise, is artificially unstable and abnormally prone to ankle sprains. Consequently, ordinary ankle sprains must be viewed as largely an unnatural phenomena, even though fairly common. Compelling evidence demonstrates that the stability of bare feet is entirely different from the stability of shoe-equipped feet.
The underlying cause of the universal instability of shoes is a critical but correctable design flaw. That hidden flaw, so deeply ingrained in existing shoe designs, is so extraordinarily fundamental that it has remained unnoticed until now. The flaw is revealed by a novel new biomechanical test, one that is unprecedented in its simplicity. It is easy enough to be duplicated and verified by anyone; it only takes a few minutes and requires no scientific equipment or expertise. The simplicity of the test belies its surprisingly convincing results. It demonstrates an obvious difference in stability between a bare foot and a running shoe, a difference so unexpectedly huge that it makes an apparently subjective test clearly objective instead. The test proves beyond doubt that all existing shoes are unsafely unstable.
The broader implications of this uniquely unambiguous discovery are potentially far-reaching. The same fundamental flaw in existing shoes that is glaringly exposed by the new test also appears to be the major cause of chronic overuse injuries, which are unusually common in running, as well as other sport injuries. It causes the chronic injuries in the same way it causes ankle sprains; that is, by seriously disrupting natural foot and ankle biomechanics.
These and other objects of the invention will become apparent from a detailed description of the invention which follows taken with the accompanying drawings.